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Old 28-08-2010, 21:13   #331
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Originally Posted by phillw View Post
Another multihull designers comments on the capsize. Comments appear at the bottom of the Anna report.

Stability « Catamaran Concepts
The one thing I was going to comment on in the rescue video was the actual transfer, which this other designer picked up on


“The rescue video is frightening for reasons outside the inverted cat issues. I wonder why the lads didn’t just get in the dinghy and make their way over to the rescue ship? The first man’s choosing to dive in and swim for it in rough seas with no buoyancy aid of any kind appears to have been a rash decision. The second fellow came so close to being mashed between the rescue ship and the inverted cat’s rudder while the two vessels ground against each other that I would say that was his moment of greatest danger. The ship was there and made the rescue, all credit to them, but what a finale to a series of near misses with tragedy.”
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Old 29-08-2010, 03:17   #332
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Thanks pelagic for the link.

Its hard to argue with Ted Clements words of Wisdom.

Quote "The consequent marketing coercion to think that bigger and faster translates to safer, more comfortable and easier to live with, or just plain better, goes largely unchallenged. I would like to think that some reconsideration of the rationale delivered to potential and trusting owners would be engendered by this incident. " Unquote
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Old 29-08-2010, 04:03   #333
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Originally Posted by Event_Horizon View Post
All valid, design is a process, which I LOVE so if posts like this keep happening you guys will keep egging me on
In stead of a thing to let go the clew could a self tailing winch be designed to, when triggered by your sensor, release the sheet in 5 foot incriments?

How could you do something similar on monohull boats where often the mainsheet is no longer near the helm?


Thanks


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Old 29-08-2010, 04:44   #334
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Originally Posted by bayview View Post
Thanks pelagic for the link.

Its hard to argue with Ted Clements words of Wisdom.

Quote "The consequent marketing coercion to think that bigger and faster translates to safer, more comfortable and easier to live with, or just plain better, goes largely unchallenged. I would like to think that some reconsideration of the rationale delivered to potential and trusting owners would be engendered by this incident. " Unquote
I actually wasn't too pleased with some of his comments. I thought his egg comment and three stooges picture was out of place. And that his assessment that "[Chris White's] qualifier suggesting that a typical couple can easily learn to safely do the necessary sailing procedures properly and in sequence on these vessels is a dodge" is outright silly.

There is no evidence to suggest that any boat in the Atlantic series is inherently unsafe. Moreover there is plenty of evidence to support his claims that a typical couple can easily learn to safely do necessary sailing procedures and in proper sequence! If the captains and sailors choose not to learn these things then that is their prerogative, regardless of how ill advised it may be. Chris White has zero obligation to completely idiot proof his boats. He is building 1.6 million dollar high performance crafts, not play pens for infants, assuming customers can learn basic safety operations is reasonable.
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Old 29-08-2010, 05:26   #335
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Sorry for the double post...

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Originally Posted by MarkJ View Post
In stead of a thing to let go the clew could a self tailing winch be designed to, when triggered by your sensor, release the sheet in 5 foot incriments?

As far as connecting the sensor to a winch, sure its absolutely possible. I mean, we have the technology. It is a question of added value vs. added complexity. If we were looking to have this picked up by a manufacturer that would be a huge area for investigation. Unfortunately the case in inventing and product development is usually "safety doesn't sell."**

I honestly have no clue how this would pan out, but I wasn't completely sold on the clew location either.

Quote:
How could you do something similar on monohull boats where often the mainsheet is no longer near the helm?
In terms of a "smart winch" yes, you could put that on a mono. Though I don't know how to go about predicting knockdowns on a mono reliably. I'd change out the bottom sensor idea in favor of a tilt sensor. (It is my duty to inform you that the rest of this is based solely on my gut feeling). The major problem I see with such a system is that when a monohull gets knocked down, at the angle when the sensor would say "ok, something strange and different is going on, it's time to do something cause the boat is being knocked over" the boat is already at an angle where it isn't seeing much wind force on the sail anyways. It may already have all the momentum it needs to carry it the rest of the way. If this were the case releasing the sail wouldn't greatly affect the outcome. Though I very well maybe completely and utterly incorrect about that and wouldn't be surprised in the least.

**Sales for automobile seatbelts were pathetic until it was gov. mandated.
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Old 29-08-2010, 06:36   #336
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Originally Posted by Event_Horizon View Post
The major problem I see with such a system is that when a monohull gets knocked down.
I'd set it at 40 degrees. It doesnt need to be a knockdown before I want the thing eased. It would be great to prevent broaches, and give a short handed crew time to get on deck. I am not a high perforamnce kinda cruiser

thanks for your ideas


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Old 29-08-2010, 12:46   #337
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At the risk of siding with the Cat folks I don't think (in general?) cat owners were that naive.
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Originally Posted by bayview View Post
Thanks pelagic for the link.

Its hard to argue with Ted Clements words of Wisdom.

Quote "The consequent marketing coercion to think that bigger and faster translates to safer, more comfortable and easier to live with, or just plain better, goes largely unchallenged. I would like to think that some reconsideration of the rationale delivered to potential and trusting owners would be engendered by this incident. " Unquote
Actually I'm not much impressed by the Clements comments. There is no question that bigger is more seaworthy and more comfortable and generally faster. Those are facts. I don't see the "wisdom" of denying them.

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Old 29-08-2010, 12:59   #338
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In stead of a thing to let go the clew could a self tailing winch be designed to, when triggered by your sensor, release the sheet in 5 foot incriments?
You could put the winch on a clutch that would let it rotate backwards or some such -- easy though there would be follow on "issues". The big money problem that I see is that the self-tailing mechanism on most winches is not going to work at all well in reverse. Fixing that might be as easy as redesigning the stripper. But, you'd also have over-ride issues if you released the line fast so you'd need to think about some kind of guide to keep the line on the winch... And, a winch that can run freely backwards is a hazard so you'd need to think about safety issues like some kind of winch handle release to prevent blunt trauma danger... All of which leads me to think that retro-fitting such a system to existing winches is going to be challenging.

Tom.
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Old 29-08-2010, 13:35   #339
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Just to put a two way winch solution out there for consideration: Harken: Captive Reel Winch

Tom
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Old 29-08-2010, 13:47   #340
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Actually I'm not much impressed by the Clements comments. There is no question that bigger is more seaworthy and more comfortable and generally faster. Those are facts. I don't see the "wisdom" of denying them.

Tom
Yes, as long as one ignores the facts that bigger takes longer to hoist , longer to trim, longer to reef, longer to change direction and longer to run from ones comfy seat inside the cabin to the sheets to release them that inturn take longer to runout.

Once a multihull gets to this size the shorthanded crew is relying on a whole heap of lucky breaks to fall their way. Annas fell the other way.

Not to mention anything about the damage such highly loaded sheets can inflict on the tired shorthanded crew.
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Old 29-08-2010, 13:50   #341
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The best solution (as decided by me) is a bungee rope of some kind inside the boom attached to the main sheet with a locking mechanism holding the sheet to the boom. The lock blows at a certain load or electronic trigger of some kind (Event Horizon's 'sensor array'). When the emergency's over you just head into the wind and snap the lock back on (the madly flogging sails, wind and rain whipping across the deck, monster waves filling the cockpit with water, circling sharks, alcohol haze, and boom to face injury would be minor inconveniences easily overcome for someone as competent as I).

See included highly technical schematic.

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Old 29-08-2010, 16:34   #342
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Originally Posted by tsmwebb View Post
Just to put a two way winch solution out there for consideration: Harken: Captive Reel Winch

Yes, in the superyacht world, winches with 'backwind' (powered reverse) capability are quite common. These winches are normally controlled by PLC. And you have a turn key EventHorizon solution if you added a couple solid state blige pump sensor (or a B&G mercury heel switch) under the hull. BUT it would be an expensive and complex solution. I bought a pair of the backwind winches for a project I worked on last year and they were £26,000.00 each! And you would have the plc and sensors to keep working., and wires to run around the boat. It's a solution that really does not meet KISS.

I am not sure how many you would sell, especially if a $50 spectra lashing solves the end problem.

Tom
[QUOTE=Mad Mike;511424]bungee rope of some kind inside the boom attached to the main sheet with a locking mechanism holding the sheet to the boom.

Yes, that's along the line of what Dragon suggested several posts above, a release (fuse or mechanical) with a second take up rope to limit the release. Its a nice idea to normally have the take up rope inside the boom to keep it out of the way. . . but that would probably require some custom boom engineering.
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Old 29-08-2010, 21:20   #343
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Originally Posted by bayview View Post
Thanks pelagic for the link.

Its hard to argue with Ted Clements words of Wisdom.

Quote "The consequent marketing coercion to think that bigger and faster translates to safer, more comfortable and easier to live with, or just plain better, goes largely unchallenged. I would like to think that some reconsideration of the rationale delivered to potential and trusting owners would be engendered by this incident. " Unquote
Hi bayview
My only comment supporting his article was relating to the actual transfer to the rescue ship, which we should look at as a lesson on how not to do it.

But now that you mention it, one of my pet peeves is the dangerous mindset some sailors try to promote… that you can “out-run” a storm or bad weather and faster/bigger is better.

I believe, the reality is all about “balance” …..meaning;
Safe speed…… balanced for the conditions
Vessel size…… balanced with the crew’s ability to manage that size.

I have little experience with cruising on large multi-hulls, so the experts here can correct me if I am mistaken.

Is not multi design based more on the idea that you want to minimize displacement and sail more on top of the water?

If so, then a larger multi does not easily translate into a larger displacement ration for comfort reasons in heavy weather.

It just gives you incredible volume and living spaces together with superb performance in moderate conditions

Have I got the right?

For monos, in heavy weather, larger displacement and having a more solid foot in the water, relates to a more comfortable ride, so bigger is nicer, but again there is still that balance and not a reason to challenge the weather.
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Old 29-08-2010, 21:36   #344
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Originally Posted by MarkJ View Post
In stead of a thing to let go the clew could a self tailing winch be designed to, when triggered by your sensor, release the sheet in 5 foot incriments?

How could you do something similar on monohull boats where often the mainsheet is no longer near the helm?


Thanks


Mark
Good idea Mark

Perhaps “hydraulics” is a way to do this.

Heavy duty hydraulic winches which have a critical stress factor, have a relief valve, which will blow by, thereby releasing pressure.

If that were engineered to release whenever it got close to flying a hull or broaching in a mono, the sheet would unwind.

I think the mainsheet though would need to be led to a self spooling drum, that was tensioned by hydraulics..... so a bit complicated
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Old 29-08-2010, 21:47   #345
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Originally Posted by Mad Mike View Post
The best solution (as decided by me) is a bungee rope of some kind inside the boom attached to the main sheet with a locking mechanism holding the sheet to the boom. The lock blows at a certain load or electronic trigger of some kind (Event Horizon's 'sensor array'). When the emergency's over you just head into the wind and snap the lock back on (the madly flogging sails, wind and rain whipping across the deck, monster waves filling the cockpit with water, circling sharks, alcohol haze, and boom to face injury would be minor inconveniences easily overcome for someone as competent as I).

See included highly technical schematic.

Attachment 18769
As you point out - once you "blow" the mainsheet gear you have a completely uncontrollable boom. That is still carrying full sail.

I am not convinced at all, even with all the thoughtful and reasoned responses, that letting go the boom automatically is the right thing to do.

The sensor array sounds promising as to me there is a direct connect between hull lifting and, "Oh, boy. This is definitely an emergency."

Couple that with Mark's idea to somehow release the sheets in measured doses and I think we are on to something.

I think manufacturers would take some time to warm up to these types of safety systems. Product liability could become a big issue. i.e. "I installed your electronic array sheet releaser 20 years ago, never serviced or tested it and I still capsized and BTW my spouse died and now I own your company."
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